[docs] Fix the broken Table sorting logic (#12569)

Author: oliviertassinari

docs/src/pages/demos/tables/EnhancedTable.js

@@ -25,8 +25,18 @@ function createData(name, calories, fat, carbs, protein) {
   return { id: counter, name, calories, fat, carbs, protein };
 }
 
+function desc(a, b, orderBy) {
+  if (b[orderBy] < a[orderBy]) {
+    return -1;
+  }
+  if (b[orderBy] > a[orderBy]) {
+    return 1;
+  }
+  return 0;
+}
+
 function getSorting(order, orderBy) {
-  return order === 'desc' ? (a, b) => b[orderBy] - a[orderBy] : (a, b) => a[orderBy] - b[orderBy];
+  return order === 'desc' ? (a, b) => desc(a, b, orderBy) : (a, b) => -desc(a, b, orderBy);
 }
 
 const rows = [